My beforementioned patents disclose a rotatable drum-type composting apparatus which is uniquely advantageous in the composting of various organic waste material. The basic apparatus comprises a drum, which is mounted for rotation about a horizontal axis, slightly above the ground or other supporting surface. The sidewalls of the drum are formed of mesh or perforated paneling, and one section of the drum wall is removable or openable to provide access for loading of compostable materials into the drum. In a typical case, the drum is loaded with organic waste materials such as leaves, grass clippings, small twigs, household waste or the like. The perforated sidewalls of the drum are covered by a generally waterproof, removable cover during the composting phase.
After being loaded with compostable materials, closed and covered, the drum is rotated about its horizontal axis for a short period of time in order to thoroughly mix the contents. Thereafter, the covered drum is kept generally motionless for a period of time, typically around two weeks, during which the composting process takes place.
Advantageously, the composting process is monitored by means of a thermometer inserted well into the body of compostable material. In a typical case, the composting process will cause the temperature of the material to increase to a level of around 150.degree.-160.degree. within two or three days. After another day or so, the temperature will tend to level off at around 130.degree. F. for several days. By the end of the second week, the temperature will have dropped back to ambient levels, signalling that the composting process has been completed.
In accordance with known procedures, after the composting process has been completed, the external cover is removed from the drum, and the drum is rotated continuously for a period of time, to cause the composted material to be sifted out through the perforated sidewalls of the composting drum.
The present invention is directed to specific improvements in the known composting apparatus focused specifically on facilitating the sifting out of the composted material as well as facilitating the access to and removal of the sifted-out material. The apparatus of the invention employs a composting drum of circular cross section supported at the opposite ends of its cylindrical walls by pairs of rollers, at least one of which is power driven. The drum is thus supported a short distance above the ground or other supporting surface, at a level such that the access door to the interior of the drum is at a height suitable for manual loading of materials into the drum. Inasmuch as loading height limitations impose a practical limit on the height above the support surface that the drum can be mounted, sifting of materials from a cylindrical drum can become inhibited by filling up of the space between the support surface and the bottom of the drum. Pursuant to the invention, a clearing bar is provided on the outer surface of the cylindrical drum, dimensioned and positioned to pass between the drum and the mounting shafts of the support rollers. On each revolution of the drum, the clearing bar sweeps clean a clearance area underneath the drum, to allow normal sifting and discharge to take place.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of a preferred embodiment of the invention and to the accompanying drawings.